Method for blanket charging glass batch in a glass furnace



Oct. 27, 1959v R. H. oLso'N 2,910,200

METHOD FOR BLANKET cHARGINc--GLASS BATCH m A GLAss FURNACE originalFiled neg. 1o, 195e 5 sheets-'sheet 1 Oct. 27, 1959 R. H. LsoN 2,910,200

METHOD FOR BLANKET CHARGING GLASS BATCH IN A GLASS FURNACE OriginalFiled Dec. 1D, 1956 5 Sheets-Sheet 2 IN VEN TUR a//Jh H, Olson d. Ne/sonand Leann/af D 50i/@Ef farm/meis R. H. OLSON METHOD FOR BLANKET CHARGINGGLASS BATCH IN A GLASS FURNAC Original Filed Dec. 10.A 1956 5Sheets-Sheet 5 INVENjroR. /a/ph H. O/son d. A. A/e/san and Lea/vara.Saab/er HITORNEYS R. H. OLSON Oct. 27, 1959 METHOD FOR BLANKET CHARGINGGLASS BATCH IN A GLASS FURNACE Original Filed Dec. 10, 1956 5Sheets-Sheet 4 INVENTOR, /a/,oh H. 0/50/7 R- H. OLSON oct; 27, 1959METHOD FOR BLANKET -CI-IARGING GLASS BATCH IN AV GLASS FURNACE OriginalFiled Dec. l0, 1956 5 Sheets-Sheet 5 s, JJ?. Nelson and Leonard D.Soub/'er' United States Patent lVIETHOD FOR BLANKET CHARGING GLASS BATCHIN A GLASS FURNACE Ralph H. Olson, Toledo, Ohio, assignor toOwens-Illinois r Glass Company, a corporation of Ohio originalapplication December I1o, 1956, serial No. 627,354. Divided and thisapplication October 15, 1957, Serial No. 690,338 l 1o claims. (cl.214-152) This invention relates to a method of blanketchlarging rawmaterials in a glass furnace, and more specically lto charging a blanketof these'materialsover the top' 1956, owned by common assignee, and isfiled for the purpose of claiming the present invention, whichincorporates such an improvement for controlling the total feeding rateof the batch feeder and embodies an improved method of blanket chargingraw batch materials to a glass melting furnace responsive to furnacedemand, wherein the total distribution rate of batch along the directionof travel of the batch feeder is varied, so as to compensate for dwelltime of the-batch'feeder during the time the traveling batch feeder isstopped to replenish f the supply of batch materials in the feederhopper from a stationary source. A ybatch feeder is utilized whereinfresh batch is distributed over the Atop of the melting areaby-discharging batch from a horizontal discharge plate by reciprocatingdischarge assistants during 'back and forth travel of the batch feederapparatusfacross yone dimension of the melter. The batch feeder must bestopped at some point `rice wherein the rate of feeding batch isvariable across both dimensions of the melter.

, Another object of this inventionisto provide a method of blanketcharging batch materials to the melter, wherein the batch feeding rateiscontrolled as an average of the demands ofthe furnace aud,vin so doing,will reduce hunting in the total batch feed rate control so as not toovercontrol said rate to adjust to variations in furnace demand.

Fig. 2 is a plan view of the batch Vfeeder inoperating n position overthe top of the melter.

along its travel across the open top of the melter to reiill its hopperwith batch. vIf the furnace has been supplied with just enough batch tomeet' its demands while the batch feederV is, operating, the dwell timeduring which it is necessary to stop thebatch feeder to refill itshopper causes the quantity of batch in the melter to fall below thefurnace demand level necessary to maintain the proper level of workingglass in the feeder during this interruption of operation of the batchfeeder.

Furthermore, in varying the total batch feeding rate during travel ofthe batch feeder, the furnace demand isv detected and relayed by a glasslevel detector and control device. Over wide variations in demand, suchaA control devicev tends to hunt for the proper feeding rate of thefeeder to supply batch to satisfy the proper level of glass in theworking zone of the furnace.

It is, therefore,an object of this invention to provide i' apparatus forand a method of blanket charging batch material to the melting zone ofopen top glass furnace, wherein a predetermined excessive quantity ofbatch, above that of the proper operating furnace demand, is distributedover a portion of the top area of the melter to compensate for the lossof feed during interruption in feeding to refill the batch feederhopper.

Another object of invention is to provide a method for -blanket chargingbatch to an open top ,glass melter,

- maintained above the feed point in the glass working- Fig. 3 is asectional end elevational View of the batch lfeeder taken along lines3-3 of Fig. 2. i

`Fig. 4 is a'fragmentary end elevational viewof the batch feeder shownin Fig. 3, and including switch mechanism for energizing the overridingcontrol circuit at predetermined positions of the batch feeder along aportion of its path of travel across the melter.

Fig. 4A is a top view of the overriding control circuit switch.

Fig. 5 is a partial side viewof the feeder apparatus, shown in operatingposition on ythe tracks and'- including thecam rail and cam for closingthe overriding control circuit switch. t Fig 6 is axschematic View,showing the electrical control circuits for varying the speedof'thedischarge drive motor as a functionof furnace demand, andincluding an overriding control circuit for increasing the speed of themotor over that set by the furnace demand control. t' The method of thisinvention consists, generally, in supporting a body of batch materialsin a feeder hopper` whichA is supported to. extend across one dimension'of the glass melting zone of an open top glass melting fur.- l

nace.` The body of batch is traveledLat a uniform-rate, back and forthacross the other dimension of the melter while feeding the batchtherefrom at a rate which varies l s along the longitudinal dimension ofthe batch feeder, and

blanket between the central and side zones of the melter.

The total rate of feedingl the batch is controlled while the batchfeeder travels, from one extremity of the `melter to the other, so'as tovary this total feedingI rate as a function of the furnace demand.l Anyvariationin furnace demand is-relayed'to vary the' total batch .feedingrate by means` of a glass level detector and control device which makesthe proper adjustment in the speed of the batch feeddrive. ln thismanner, the batch feeder always supplies enoughV batch to the melter tomeet'furnace'r'equirements, so that a desired level of molten glass'iszone of the furnace. However, this may only be accomplished while thebatch feeder is operating, and since it is necessary to periodicallystop the batch feeders travel and interrupt its operation in order toreplenish the body of batchmateiial carried by the hopper, the level ofthe blanket carried by the melter lags behind furnaceV demand. When thebatch feeder is again put into operation after refilling, the demandforbatch has increasedto a point where the glass level control calls forr a`Sharp feeding rate increase. In order for the batch feeder to 2,91a2o0a s I Patented', Oct. 27, 1959` ythere load the hopper batch. Spacedfrom .are batch bins 18 supported on structural columns 19.

Y 3 again catch up with the furnace demand level, the glass leveldetector adjusts the batch rate to vary through wide ranges oscillatingover and under the rate for desired operating level in a manner ofhunting The huntmg may add batch to the blanket in a manner so as tovary the working glass levelin the Working zone of the furnace to causesignificant ,variations in working glass gob size and ultimately affectthe quality of the Ware being produced therefrom. To compensate for thepause in operation for refilling the batchfeeder hopper, and to decreasethe hunting effect of the total feed rate controls after the batchfeeder returns to operation, this invention contemplates increasing thetotal feeding rate above that corresponding to furnace demand during aportion of the travel of the batch feeder and thereby supply an excessof batch to a portion of the blanket above that normally `demanded bythe furnace dining that time. This excess is controlled to equal thequantity of batch that is melted during the pause for hopper refill, sothat when the batch feeder resumes operation the level of the batchblanket will approximately equal the then current furnace demand level`By including a droop correction control device connected responsive tothe glass level detector and control device, the demand variations ofthe furnace that may occur during operation of the batch feeder will bevaveraged by the droop correction control to reduce the hunting effect ofthe glass level control in relaying adjustments to the batch feedingrate.

Turning now to the iigures, Fig. l illustrates a conventional open topglass furnace referred to generally at 10, supported on a structuralbase 11, and comprises a melter chamber 12 communicating with a renerchamber 13 through a submerged throat passage 14. A feeder lhopperassembly 15 is supported on tracks 16 over the top of melter 12 andassembly 15 is adapted for movement longitudinally of melter 12 onrollers 17 traveling along tracks 16. Rollers 17 are propelled alongtracks 16 by a conventional constant speed driving device (not shown),which reverses direction at each longitudinal end of melter 12. It istimed to stop or dwell periodically at the end of melter 12 oppositethroat passage 14, and of assembly 15 from a supply of the outer endWall of melter 12 Bins 18 are utilized to store raw batch materials yfortransfer to feeder hopper assembly 15 by conveyor 20. The hopper ofassembly 15 is loaded while stationary at its extremity of travel to theright hand side of Fig. l.

Referring now to Figs. 2 and 3, itis seen that the feeder hopperassembly 15 comprises an elongated funnel-shaped hopper 21 supported bya frame 22 mounted on rollers 17. Longitudinally of the hopper 21 is ascrew element 23 mounted for rotation therein. An electric motor 24 ismounted on a bracket 25 at one end of hopper frame 22, and drives screw23 through belt 26 and pulley 23a .to distribute the batch uniformlythroughout the length of hopper 21.

'I'he lower funnel portion of hopper 21 is housed between longitudinalmembers of frame 22 and has a discharge opening 27 (Fig. 3) to permitgravity feeding of vbatch material contained in hopper 21 onto anelongated discharge lip member 28 rigidly mounted on frame 22 belowdischarge opening 27. Discharge lip member 28 l receives and supportsbatch material in hopper 21 and has suiiicient width, so that, as batchmaterial is discharged from hopper 21 onto lip 28, the angle of reposeof the batch supported thereon will prevent therbatch from spilling overthe discharge extremity 28a of lip member 28. Along the one longitudinaledge of lip member 28 is mounted a plurality of discharge assistants formoving batch otf of lip member 28.

As shown, these discharge assistants are illustrated as a plurality ofreciprocating blade elements 29 pivoted about a longitudinal pivot axis30 overlying lip member 28 and along the side at the lower end ofdischarge opening 27 a curtain of batch over the top of the melter.

of hopper 21. A levery arm extension 29a is provided integral on each ofblade members 29 and extends outwardly of opening 27. Shaft 3l isjournaled at its ends in brackets 32 mounted on hopper frame 22 so thatit is parallel to and overlying blade members 29. Pulley 33 is keyed tothe end of shaft 31 for imparting rotation transmitted from a variablespaced D.C. motor 35 and belt 34. Motor 35 is mounted on frame 22 bybracket 38. The variable speed feature of motor 35 is utilized to varythe total feeding rate ofthe discharge assistants, which will behereinafter described more fully. A plurality of connecting rods 36 areeach pivoted at one end on pins 37 in their respective lever arms 29a ofblade members 29 at pins 37. Pins 37 are carried in any selected hole 2%of a series of such holes along each lever arm 29a, and are readilyremovable for adjusting the connection of'connecting rod 36 to lever arm29a. The other end of connecting rod 36 is provided with an eccentricbearing member 39 clamped about shaft 31 and threaded onto lthe endofconnecting rod 36 at U-clamp 39a. Connecting rod 36 has a threadedadjustment t0 adjust 'its length when changing the lower connection tolever arm 29a between holes 29b. Likewise, the throw of the .eccentricsare adjustable by providing eccentric bearing members 39 of varioussizes, which may be easily interchanged by threading and unthreading atU-clamp 39a.

During operation of the feeder hopper assembly 1S, motor 35 drives shaft31 in one direction. The rotation at shaft 31 is converted to reciprocalmotion at blade member 29 through the action of eccentric 39 andconnecting rod 36 on lever arm 29a. The length of stroke of thereciprocating motion of a given blade member 29 is adjustable by varyingits point of connection to connecting rod 36 along the length of itslever arm 29a or by changing the throw of eccentric 39, or both.

In the figures is shown an arrangement of four driving connections 39,36 and 37 for reciprocating blade members 29. It is contemplated by thisinvention that the blade members 29 may be individually varied in lengthof stroke, thereby varying one from the other the effective rate ofdischarging batch material from lip member 28.

In Fig. 4, a double pole double -throw control switch assembly 4t) ismounted on bracket 41 fastened to the side of hopper frame 22 andoverlies cam track 42. A cam Vtrack support member 43 is rigidlyconnected longitudinally along the bottom of track 16. Cam arm 44 isrotatable about pivot pin 46 in switch assembly 4i) and carries arotatable cam roller 45 at the lower end thereof. The upper end of camarm 44 carries a transverse electrical contact bar 47. Leaf spring 48 isattached at one end on switch assembly 40 and lies along cam arm 44 tobear against it. Spring 48 normally holds cam arm 44 so that itscontacter bar 47 makes an electrical connection across terminals 49 ofswitch 40 (Figs. 4A and 6) and normally close only the field circuit ofvariable speed D.C. motor 35. However, during a portion of the travel ofhopper assembly 15 away from throat outlet 14 (to the right in Fig. 4)cam arm 44 is pivoted, against the force of spring 48, by cam 45engaging cam track 42 along its lengthV and contactor bar 47 is shiftedto make an electrical connection across terminals 50 of switch 40 (Figs.4A and 6) to connect the overriding control circuit in series with thelield circuit of motor 35, and thereby increase the speed of the motorby connecting a predetermined amount of electrical resistance in serieswith the lield windings 51 of motor 35.

In practicing the method of this invention, feeder hopper assembly 15 isreciprocally moved back and forth across one dimension of the furnace.During this time, motor 3S impartsV reciprocating motion to blademembers 29 to move batch material` deposited on discharge lip member 28over its discharge extremity 28a and lay Along the length of dischargelip member 28 these discharge l assistants (blade members 29) arefeeding batch at a varying rate determined by thevvariable length ofreciprocating stroke of blade members 29.

lThe total batch laying rate of the system may be conf.

4trolled to the demands of the furnace by varying the speed of motor 35,which vdrives all of Vthe discharge assistants 2,2. This is accomplishedthrough the control circuits for'motor 35, shown schematically in Fig.6.

A conventional glass level probe 52 is mounted in the furnace forehearthand connected electrically to a glass level detector and control device53 of the type shown and described in U.S. Patent No. 2,613,443 to M. A.Helmick, entitled Glass Level Recording Mechanism. Glass level device 53is connected in series with a conventional automatic reset device ordroop correction control 54. f A.C. motor 55 which has Van operativeconnection to adjust the-setting of rheostat 56, is electricallyconnected with the droop correction control device 54 to rotate betweenlimits'defined by limit switches 55m/1d 59 and adjust the setting up ordown of rheostat Sti, thereby increasing or decreasing, respectively,its amount of resistance in the field circuit of motor 35. Variablerheostat 56 is normally connected across terminals 49 53 initiates anadjustment of variable rheostat 56 through' motor' 55 to appropriatelydecrease the field resistance and thereby decrease the'speed of motor35, and conw versely, when the glass level falls below normal, the glasslevel detector device 5,3' initiates an adjustment of rheostat 56through motor 55 to appropriately increase the field resistance andthereby increase the speed of motor T he droop correction control device54 monitors these demandsignals given by the glass level detector 52-53and averages them so as to reduce the Lhuntirig eifect of the motorcontrols as glass demands vary.

. As previously mentioned, this circuit is normally connected to motorfield windings 5i through connectionfat terminals 49, however, on aportion of the travel of -hopper assembly 15 away from melter throat`outlet 1li,

the throw of switch it? is reversed by cam 45 engaging cam track 42.Switch 4% is then set to electrically connect the terminals 5d andconnect the resistance 57 of an overriding control circuit in serieswith variable resistance 56 and field windings 51. Up to this point, the

speed of motor has been controlled to feed batch as the furnace levelvariations demanded, but during the time the resistance 57 is connectedtoiield windings 51 connected, and the feeding rate will be decreasedduring' the remainder of the travel of hopper assembly 15 in thatdirection. Since the droop correction device averages the demands over acycle of travel, the total batch feeding rate will be decreased belowthe corresponding furnace demand until the excess batch is melted torestore the4 system to balance. During part of the time the system isreturning to balance, the hopper assembly comes to rest at the end ofmelter 10 and hopper 21 is refilled. Thus, the excess batch laid over aportion ofthe travel to the refill station compensates for the lost.batch -feeding time while the batch feeder is stopped for refilling.

It is contemplated in this inventionthat this excess in batch 'beingapplied` may be varied in twodimensions. First, the length ofthe span`over which it is applied may `be varied by providing a telescopicallyadjustable `length of cam track 42 which may be lengthenedor shortenedby repositioning its end mounting position along its sup',- port member43 (Figs. k4 and Se). And second, thedepth at which the excess of batchis applied .over this span may be variedby increasing or decreasing theamount of the resistance 57 in the overriding control circuit.

Also, the span of travel of hopper assembly 15 and point at which theexcess of batch is to be .applied may vary by varying the location ofany selected length yof cam track 4 2, or by installing a plurality ofspaced cam track sections over selected spans. For sake ofrsimplicity ofillustration, howerrerponlyl a ysingle length of cam ytrack 42 is showninthe figures. Y

This invention also, includes a method of feeding the batch in blanketfashion so that the total feeding rate is variable responsive to furnaceVdemands without the aforementioned feature of laying an excessiveportion of batch.` The hookup of the apparatus for this lattermentionedmethod is demonstrated in Figi. 7.

The glass level probe 52 is -mounted in the furnace forehearth and hasan operable electric connection to the glass level detector device 53,as previously described. Power is applied to the detector device 53 fromthe A..C. main lines and the motor 55 of the detector device 53 isloperated responsive to the glass level detected through the probe V52.Motor `55 operates inj either direction of vrotationto adjust rheostat56,. Rheostat-St comprises a resistance in series with the fieldwindings 51 of motor 35. Motor Y35 drives the discharge `assistants 29,`through eccentrics 39 and their connecting rods 36, as previouslydescribed. ,1. y

Thus, as the demands of the furnace increase, as measured by the levelof glass in the feeder forehearth of the furnacel being too low, themotor 55 of glass detector device 53' adjusts rheostat 56 to introduceadditional rewsistance into the field circuit of motor 35, thereby: in,

creasing its speed. and the total rate of feeding bythe Y dischargeassistants (29) until the glass `level in the forehearthreturnstonormal. `At this point, the motor 55 operates to'cut out a portion ofthe resistance56 and the totali feeding rate of the discharge assistantsis decreased. i

lf the 4glass level in the forehearth rises too high, motor 55 of theglass level detector 53 reduces the resistance 56 in the eld circuit 51of motor 35 to slow it-down Y accordingly andthe total rate of batch fedby the discharge assistants is decreased. As previously mentioned,v

the hopper unit 15 is traveling at a uniform speed across the top of themelter portion 12 of the furnace.

e lt will, of course, be understood that 'various details.

. one direction of movement ofthe hopper relative tothe furnace, andincreasing the batch feeding rate above that corresponding to furnacedemand for a portion Yof the movement of the hopper in the otherdirection relative to thefurnace.

2f-The method of batch feeding an open top glass furnace'icomtprisingreoiprocally moving a batch feeding hopper' over the top of said furnacealong ,one dimension of the furnace, controlling the batch feeding rateof said hopper according to an average of the variations of the furnacedemand throughout one direction of movement of the hopper relative tothe furnace, increasing the batch feeding rate above that correspondingto said average of the furnace demand for a portion of the movement ofthe hopper in the other direction relative to the furnace, and returningthe batch feeding rate to that corresponding to said average of thefurnace demand during the last portion of the movement of the hopper insaid other direction.

3. The method of batch feeding an open top glass furnace comprisingreciprocally moving a batch feeding hopper over the top of said furnacetoward and away from the furnace outlet, controlling the batch feedingrate of said hopper as a function of the furnace demand during movementof the hopper toward said furnace outlet, and increasing the batchfeeding rate above that corresponding to furnace demand for a portion ofthe movement of the Ahopper away from said furnace outlet, and

resuming the batch feeding rate as a function of furnace demand duringthe last portion of the movement of the vhopper away from said furnaceoutlet.

4.` The method of batch feeding an open top glass furnace by a feedinghopper extending across one dimension of such furnace, comprisingreciprocally moving the batch feeding hopper over the top of saidfurnace along the other furnace dimensions, feeding batch from thehopper at different rates along the length thereof to deposit varyingamounts of batch between diiferent areas of the furnace, controlling thetotal batch feeding rate of said hopper as a function of the furnacedemand during movement of the hopper in one direction relative to thefurnace, and increasing the total batch feeding rate above thatcorresponding to the furnace demand for a portion of the movement of thehopper in the other direction relative to said furnace.

5. Themethod of batch-feeding an open top glass furnace by a feedinghopper extending across one dmensionof such furnace, comprisingreciprocally moving the batch feeding hopper over the top of saidfurnace along the other furnace dimensions, feeding batch from thehopper at different rates along the length thereof to Adeposit varyingamounts of batch between different areas of the furnace, controlling thetotal batch feeding rate of said-hopper as a function of the furnacedemand during movement of the hopper in one direction relative to thefurnace, increasing the total batch feeding rate above thatcorresponding to the furnace demand for a portion of the movement of thehopper in the other direction relative to said furnace, and resuming thetotal `batch feeding rate as a function of furnace demand during v Ithelast portion fof the movement of the hopper in said .other directionrelative to said furnace.

6. The method of batch feeding an open top glass furnace comprisingsimultaneously feeding batch across one entire dimension of the furnacein a vertical curtain pattern having a different effective batch feedingrate in one portion of said lpattern than `at the remaining portionsthereof, reciprocally moving said vertical curtain pattern along theother dimension of the furnace, controlling the total batch feeding rateof the vertical curtain pattern as a. function of the furnacedemand-throughout above that corresponding to furnace demand for aportion of the movement of the vertical curtain pattern in the otherdirection relative to said furnace.

7. 'Ihe method of batch feeding an opentop glass furnace comprisingsimultaneously feeding batch across one entire dimension of the furnacein a vertical curtain pattern having a different effective batch feedingrate in one portion of said pattern than at the remaining portionsthereof, reciprocally moving said vertical curtain pattern along theother dimension ofthe furnace, controlling the total batch feeding rateof the vertical curtain pattern as a function of the furnace demandthroughout movement of thepvertical curtain pattern `inrone directionalong said other furnace dimension, increasing the total batch feedingrate of the vertical curtain pattern above that corresponding to furnacedemand for a portion of the movement of the vertical curtain pattern intheother direction relative to said furnace, and decreasing the totalbatch feeding rate of the vertical curtain pattern to that correspondingto furnace demand during the last portion of the movement of thevertical curtain pattern in said other direction relative to saidfurnace.

8. The method of blanket feeding glass batch into an open top glassfurnace, comprising reciprocally moving a body of said batch along onedimension of the furnace, said body being suspended to extend acrosssaid top opening transversely of said dimension of the furnace,simultaneously feeding batch from said Ymoving body, varying the rate offeeding said batch along the length of said lbody, controlling the totalrate of feeding batch from said moving body as a function of the furnacedemand, and increasing said controlled total rate of feeding batch apredetermined yamount responsive to the position of said body along saidone furnace dimension.

9. The method of blanket feeding glass batch into an open top glassfurnace, comprising reciprocally moving a body of said ybatch along onedimension of the furnace, said body being suspended to extend acrosssaid top opening transversely of said dimension of the furnace,simultaneously feeding -batch from said moving body, varying the rate offeeding said batch along the length of said body, and controlling thetotal rate of feeding batch from said moving body according to anaverage of a function of the furnace demand. Y l0. The method of batchfeeding an open top glass furnace comprising simultaneously feedingbatch across one entire dimension of the furnace in a vertical curtainpattern having a different effective batch feeding rate in one portionof said pattern than at the remaining portions thereof, reciprocallymoving said vertical curtain pattern along the other dimension of thefurnace, and controlling the total batch feeding rate of the verticalcurtain pattern according to an average of a function of the furnacedemand throughout movement of the vertical curtain pattern in onedirection along said other furnace dimension.

References Cited in the le of this patent UNITED STATES PATENTS2,709,530 Haley et al May 31, 1955

